Tag: extreme weather

Why 40°C is bearable in a desert but lethal in the tropics

Posted on by amanda.woodman-hardy
Phew: heat plus humidity can make Bangkok an uncomfortable place in a heatwave.
Pavel V.Khon/SHutterstock

This year, even before the northern hemisphere hot season began, temperature records were being shattered. Spain for instance saw temperatures in April (38.8°C) that would be out of the ordinary even at the peak of summer. South and south-east Asia in particular were hammered by a very persistent heatwave, and all-time record temperatures were experienced in countries such as Vietnam and Thailand (44°C and 45°C respectively). In Singapore, the more modest record was also broken, as temperatures hit 37°C. And in China, Shanghai just recorded its highest May temperature for over a century at 36.7°C.

We know that climate change makes these temperatures more likely, but also that heatwaves of similar magnitudes can have very different impacts depending on factors like humidity or how prepared an area is for extreme heat. So, how does a humid country like Vietnam cope with a 44°C heatwave, and how does it compare with dry heat, or a less hot heatwave in even-more-humid Singapore?

Weather and physiology

The recent heatwave in south-east Asia may well be remembered for its level of heat-induced stress on the body. Heat stress is mostly caused by temperature, but other weather-related factors such as humidity, radiation and wind are also important.

Our bodies gain heat from the air around us, from the sun, or from our own internal processes such as digestion and exercise. In response to this, our bodies must lose some heat. Some of this we lose directly to the air around us and some through breathing. But most heat is lost through sweating, as when the sweat on the surface of our skin evaporates it takes in energy from our skin and the air around us in the form of latent heat.

annotated diagram of person
How humans heat up and cool down.
Take from Buzan and Huber (2020) Annual Review of Earth and Planetary Sciences, Author provided

Meteorological factors affect all this. For example, being deprived of shade exposes the body to heat from direct sunlight, while higher humidity means that the rate of evaporation from our skin will decrease.

It’s this humidity that meant the recent heatwave in south-east Asia was so dangerous, as it’s already an extremely humid part of the world.

The limit of heat stress

Underlying health conditions and other personal circumstances can lead to some people being more vulnerable to heat stress. Yet heat stress can reach a limit above which all humans, even those who are not obviously vulnerable to heat risk – that is, people who are fit, healthy and well acclimatised – simply cannot survive even at a moderate level of exertion.

One way to assess heat stress is the so-called Wet Bulb Globe Temperature. In full sun conditions, that is approximately equivalent to 39°C in temperature combined with 50% relative humidity. This limit will likely have been exceeded in some places in the recent heatwave across south-east Asia.

In less humid places far from the tropics, the humidity and thus the wet bulb temperature and danger will be much lower. Spain’s heatwave in April with maximum temperatures of 38.8°C had WBGT values of “only” around 30°C, the 2022 heatwave in the UK, when temperatures exceeded 40°C, had a humidity of less than 20% and WBGT values of around 32°C.

Two of us (Eunice and Dann) were part of a team who recently used climate data to map heat stress around the world. The research highlighted regions most at risk of exceeding these thresholds, with literal hotspots including India and Pakistan, south-east Asia, the Arabian peninsula, equatorial Africa, equatorial South America and Australia. In these regions, heat stress thresholds are exceeded with increased frequency with greater global warming.

In reality, most people are already vulnerable well below the survivability thresholds, which is why we can see large death tolls in significantly cooler heat waves. Furthermore, these global analyses often do not capture some very localised extremes caused by microclimate processes. For example a certain neighbourhood in a city might trap heat more efficiently than its surroundings, or might be ventilated by a cool sea breeze, or be in the “rain shadow” of a local hill, making it less humid.

Variability and acclimatisation

The tropics typically have less variable temperatures. For example, Singapore sits almost on the equator and its daily maximum is about 32°C year round, while a typical maximum in London in mid summer is just 24°C. Yet London has a higher record temperature (40°C vs 37°C in Singapore).

Given that regions such as south-east Asia consistently have high heat stress already, perhaps that suggests that people will be well acclimatised to deal with heat. Initial reporting suggests the intense heat stress of the recent heatwave lead to surprisingly few direct deaths – but accurate reporting of deaths from indirect causes is not yet available.

On the other hand, due to the relative stability in year-round warmth, perhaps there is less preparedness for the large swings in temperature associated with the recent heatwave. Given that it is not unreasonable, even in the absence of climate change, that natural weather variability can produce significant heatwaves that break local records by several degrees Celsius, even nearing a physiological limit might be a very risky line to tread.

—————————–

 

This blog is written by Cabot Institute for the Environment members: Dr Alan Thomas Kennedy-Asser, Research Associate in Climate Science; Professor Dann Mitchell, Professor of Climate Science, and Dr Eunice Lo, Research Fellow in Climate Change and Health, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Alan Kennedy-Asser
Alan Kennedy-Asser
Dann Mitchell
Dann Mitchell
Eunice Lo
Eunice Lo

Prehistoric Planet: TV show asked us to explore what weather the dinosaurs lived through

Posted on by janet.crompton
Apple TV+, CC BY-NC-SA

When conjuring up images of when dinosaurs ruled the planet we often think of hot and humid landscapes in a world very different from our own. However, the new TV series Prehistoric Planet, narrated by Sir David Attenborough, shows dinosaurs living and indeed thriving in many types of environments, including colder regions where snowstorms, freezing fog and sea-ice were commonplace.

When the show’s producers first approached us to help understand the kinds of weather and environment that dinosaurs lived in before being wiped out around 66 million years ago, it prompted us to tackle a problem that has existed in palaeoclimate modelling for decades. That was, when scientists like us used computers to simulate, or “model”, the climate of prehistoric Earth, the models tended to make the poles much colder than evidence from fossils and rocks suggested they had actually been.

For the TV series, not only have we improved our models, but we have run the computer programmes for longer than anybody else has ever done to get the models as close to ancient “reality” as possible.

Prehistoric Planet depicts CGI dinosaurs based on the latest research.
AppleTV+, CC BY-NC-SA

The producers, the BBC’s Natural History Unit, needed to know about the weather so they could film “real world” locations similar to those that existed in the past where dinosaurs lived. But most of what we know about the climate that long ago comes from indirect “proxy” evidence, such as leaf fossils and traces of certain chemicals in rocks, which can only reconstruct the average climate over decades or centuries. This is where the narrative of a much hotter and more humid Cretaceous world comes from.

This narrative isn’t exactly wrong, but it doesn’t tell the whole story since weather and climate behave differently. For instance, even in today’s warming world a place like Texas, largely hot and humid, recently experienced widespread snowfall. Geologists a million years from now will spot the sudden global warming – but not the freak snowstorm. Nonetheless, modelling the the prehistoric equivalent of these snowstorms is important since we know warmer worlds will experience greater weather extremes. And these extremes will have largely determined which regions were completely inhospitable to dinosaurs.

Surface wind speed and precipitation through a typical year 69m years ago. An index of 1 means no visibility beyond 10 metres.

How do we know what the weather was like?

Unfortunately, although fossils give us many clues as to past climate, most cannot directly tell us what the weather was on a day to day basis.

So, for a given place on Earth, how do we know what the weather was on, say, May 27 some 66 million years ago? To do this we need to employ a computer simulation of the climate, similar to the ones used to look at future climate change today. These models are based on fundamental physical and biological processes which remain constant with time. It is therefore possible to adjust them for ancient worlds, even if we don’t know precise details like where or how high the mountains were, or exactly how much carbon dioxide was in the atmosphere.

We can then check these models using some of the ancient climate proxies, such as fossilised leaves, coral or rocks which contain traces of what conditions were like at the time. If our model matches up with the proxies – and it did – then we can be confident it is simulating typical weather at the time.

So what did we learn from modelling the climate of 66m years ago?

Our model found there would have been intense blizzards in Antarctica, for instance, “category six” hurricanes (something we are likely to see in our lifetimes) buffeting the mid and low latitudes and extensive, ever present, fog banks creating murky winters under polar cloud caps.

In a warmer world the water cycle is intensified over the poles. This meant more water in the air, and large parts of the planet would have been very foggy almost all the time (Source: modelling work by the authors)

This doesn’t immediately sound like a dinosaur-friendly environment. However, the old misconception that dinosaurs were cold blooded, thus requiring a warm climate for survival has for the most part already been dismissed. The new paradigm is that dinosaurs were warm blooded, and could to some extent regulate their internal temperature, like mammals do today.

This would be essential to survive large swings in temperature, driven by varied weather patterns, particularly in the polar regions. Our modelling therefore backs up recent fossil discoveries which show that some dinosaur species were cold-adapted, could see in low light conditions (useful in those huge fog banks), and thrived year-round near the poles.

Dinosaur in snow
Pachyrhinosaurus surviving and thriving.
AppleTV+, CC BY-NC-SA

The Prehistoric Planet scenes with the chilly Pachyrhinosaurus were set in Alaska, and demonstrate why the show wanted check its accuracy with climate models. We have an idea what the conditions would have been like there 66m years ago thanks to detailed fossils of plants, dinosaurs and other animals, yet the old models would have predicted intensely-cold and lifeless tundra.

Our model instead matches up with the fossil evidence, and predicts forests right up to the margins of the Arctic Ocean at 82°N – much further north than any trees today. In the summer, dinosaur food would have been abundant, but in the long dark winters it would have been more difficult to find, particularly as both fossils and modelling suggests it was so foggy.

Dinosaurs survived for a remarkable 165 million years. Tyrannosaurus Rex lived much closer to present day humans than it did to Stegosauruses, for instance. They managed to survive so long because they were resilient and adaptable to changeable environmental conditions, much like mammals are today. Our work for Prehistoric Planet shows that they were able to survive through greater extremes in temperature, stormier weather, and more extreme droughts than humans have experienced – so far.The Conversation

————————–

This blog is written by Cabot Institute for the Environment members Dr Alex Farnsworth, Senior Research Associate in Meteorology, and Paul Valdes, Professor of Physical Geography, University of Bristol; and Robert Spicer, Emeritus Professor of Earth Sciences, The Open University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

University of Bristol welcomes five Met Office Research Scientists as part of the new Met Office Academic Partnership

Posted on by janet.crompton

 

Image Credit: Federico Respini on Unsplash

In spring of 2020 the University of Bristol joined a prestigious alliance of the Met Office and six University Research Institutes that brings together expertise in weather and climate science.  The exciting, new Bristol Met Office Academic Partnership (MOAP) is focussed on the theme of “weather and climate hazards for decision making.” The aim is to align research interests through combining the Met Office world-leading ability in weather forecasting and the hazard and impact modelling expertise we have at Bristol.

A core part of the MOAP is to embed Met Office expertise within the University and to develop cross-disciplinary research in our key theme areas. We are, therefore, delighted to announce five new part-time Joint Bristol – Met Office Faculty members of staff who began working with us at the beginning of April.

Our Joint MOAP Chair based at the Met Office, Professor Chris Hewitt commented:

“We were delighted to welcome the University of Bristol to the Met Office Academic Partnership last year, and are excited that there will be five new joint faculty positions for Met Office scientists to cement the collaboration with the University’s experts working on research topics of mutual interest.”

The collaborative research will come under four interchangeable, themes:

  • Weather, climate and environmental hazards (e.g. volcanic hazards, heat waves, storms).
  • Impact and risk-based predictions.
  • Resilience to hazards and weather.
  • Climate services for making decisions.

The theme areas are co-led by eight University of Bristol researchers from Earth Sciences, Geographical Sciences and Civil Engineering and eight Met Office scientists. The new positions will work closely with the theme co-leads and have been strategically placed across the University Faculties to enhance collaboration and develop new research opportunities, particularly in the lead up to COP26.

University of Bristol-based MOAP Joint Chair, Dr Dann Mitchell says:

“We are really excited with the new joint faculty positions starting at Bristol. They represent the full spectrum of our partnership with the Met Office, from fundamental science for weather and climate hazards, to end user engagement. They will sit across three of our faculties and help solidify cross-disciplinary links between weather and climate, and the impacts on society, such as through health and hydrological modelling.”

The Faculty of Science welcomes three of the appointments: Dr Lizzie Kendon, a Science Manager and Met Office Fellow looking at high impact weather events using very high-resolution climate models, Dr Matt Palmer who leads the team at the Met Office who research sea level and ocean heat content and Dr Joseph Daron a Science Manager for International Climate Services at the Met Office.

The Faculty of Engineering welcomes our fourth appointment Dr Fai Fung who is the UK Climate Projections Climate Services Manager.. Our fifth appointment, Dr Dan Bernie, is the Science Manager for the UK Climate Resilience Team at the Met Office and is welcomed by the Faculty of Health Sciences. With regular MOAP meetings underway and events such as the CMIP6 Data Hackathon now open for applications we are excited to begin working with our new colleagues to develop a strong, collaborative relationship between Bristol and the Met Office.

The new appointments will work closely with The Cabot Institute for the Environment, Jean Golding Institute and Elizabeth Blackwell Institute to deliver cutting-edge research in weather and climate science

For further enquiries about the MOAP we can be contacted at bris-moap-coordinator@bristol.ac.uk.

———————————

This blog is written by Dr Emma Stone (Bristol MOAP Project Manager).

Emma’s role as MOAP project Manager, previously with a background in climate science, is to assist with and coordinate MOAP-related activities working alongside the MOAP Joint Chairs, Research Advisory Panel and theme co-leads to identify potential research opportunities between the University and the Met Office and see these through to development. Emma is a key point of contact for internal and external researchers, collaborators, funders and support staff.

Dr Emma Stone

 

 

 

 

 

Image at start of article credit: Federico Respini on Unsplash

Coconuts and climate change

Posted on by janet.crompton

Before pursuing an MSc in Climate Change Science and Policy at the University of Bristol, I completed my undergraduate studies in Environmental Science at the University of Colombo, Sri Lanka. During my final year I carried out a research project that explored the impact of extreme weather events on coconut productivity across the three climatic zones of Sri Lanka. A few months ago, I managed to get a paper published and I thought it would be a good idea to share my findings on this platform.

Climate change and crop productivity

There has been a growing concern about the impact of extreme weather events on crop production across the globe, Sri Lanka being no exception. Coconut is becoming a rare commodity in the country, due to several reasons including the changing climate. The price hike in coconuts over the last few years is a good indication of how climate change is affecting coconut productivity across the country. Most coconut trees are no longer bearing fruits and those that do, have nuts which are relatively very small in size.

Coconut production in Sri Lanka

Sri Lanka is among the top 5 largest producers of coconut, alongside Indonesia, Philippines, India and Brazil (FAOSTAT, 2014). Coconut is one of the major plantation crops in Sri Lanka and is second only to rice in providing nutrition (Samita & Lanka, 2000). Coconut cultivation represents 1/5th of the agricultural land of the country and significantly contributes to Sri Lanka’s Gross Domestic Product, export earnings and employment (Fernando et al., 2007).

Mature coconuts develop approximately eleven months after inflorescence opening (Figure 1). Of this, the first three months after inflorescence opening is said to be the most critical period as the young nuts are susceptible to climatic variation (Ranasinghe et al., 2015).

Figure 1: Development stages of a coconut bunch (Source: Coconut Research Institute, Sri Lanka)

The coconut yield is influenced by climatic variables such as rainfall, temperature and relative humidity in addition to other external factors such as pest attacks, diseases, crop management, land suitability and nutrient availability (Peiris et al., 2008). Optimum weather conditions for the growth of coconut include a well distributed annual rainfall of about 1500 mm, a mean air temperature of 27°C and relative humidity of about 80-90% (Peiris et al., 1995).

Impact of extreme weather on coconut productivity

Our study analysed the impact of extreme weather events considering daily temperature and rainfall over a 21-year period (between 1995 and 2015) at selected coconut estates in the wet, dry and intermediate zones of Sri Lanka. The study revealed drought conditions during the first four months after inflorescence opening, had a negative impact on the coconut harvest in the dry and intermediate zones (as revealed by the statistical analyses and the model relationships developed in this study). Possible reasons for this include reduced pollen production due to the exposure of male flowers to elevated temperature (Burke, Velten, & Oliver, 2004) and flower and fruit abortions caused by high temperatures and absence of rainfall over an extended period of time (Nainanayake et al., 2008).

Drought conditions not only disrupt the physiological functions of the coconut palm, but also
contribute to incidences of pest attacks. At present, the Coconut Black Beetle and the Coconut Red
Weevil pose the greatest threat to coconut plantations in Sri Lanka. Drought conditions are very
conducive for Coconut Black Beetles to pupate deep in the soil (Nirula, 1955).

Implications of the findings

This study reinforces the importance of raising awareness on the implications of climate change on crop productivity. During my visits to the coconut plantations, the superintendents of the estates as well as the labourers appeared to be aware of the warming trend of the climate. They had adopted soil moisture conservation methods such as mulching, burying coconut husks and growing cover crops to prevent extreme evapotranspiration. These are short term solutions. If we are to think about sustaining the coconut cultivation in the long-term, it is important to focus our efforts on developing drought tolerant hybrids. Global climate is projected to change continuously due to various natural and anthropogenic reasons. Policy makers and market decision makers can utilize the knowledge on how coconuts respond to drought conditions to formulate better policies and prices. This information can enable us to be better prepared and minimize loss and damage caused by a drought resulting from climate change.

References

Burke, J. J., Velten, J., & Oliver, M. J. (2004). In vitro analysis of cotton pollen germination. Agronomy Journal, 96(2), 359–368.

FAOSTAT. (2014). Retrieved January 7, 2017, from http://www.fao.org/faostat/en/#data/QC/visualize

Fernando, M. T. N., Zubair, L., Peiris, T. S. G., Ranasinghe, C. S., & Ratnasiri, J. (2007). Economic Value of Climate Variability Impacts on Coconut Production in Sri Lanka.

Nainanayake, A., Ranasinghe, C. S., & Tennakoon, N. A. (2008). Effects of drip irrigation on canopy and soil temperature, leaf gas exchange, flowering and nut setting of mature coconut (Cocos nucifera L.). Journal of the National Science Foundation of Sri Lanka, 36(1), 33–40.

Nirula, K. K. (1955). Investigations on the pests of coconut palm. Part II Oryctes rhinoceros L. Indian Coconut Journal, 8(4), 30–79.

Peiris, T. S. G., Hansen, J. W., & Zubair, L. (2008). Use of seasonal climate information to predict coconut
production in Sri Lanka. International Journal of Climatology, 28, 103–110. http://doi.org/10.1002/joc

Peiris, T. S. G., Thattil, R. O., & Mahindapala, R. (1995). An analysis of the effect of climate and weather on coconut (Cocos nucifera). Journal of Experimental Agriculture, 31, 451–460.

Ranasinghe, C. S., Silva, L. R. S., & Premasiri, R. D. N. (2015). Major determinants of fruit set and yield fluctuation in coconut (Cocos nucifera L .). Journal of National Science Foundation of Sri Lanka, 43(3), 253–264.

Samita, S., & Lanka, S. (2000). Arrival Dates of Southwest Monsoon Rains – A Modeling Approach. Tropical Agricultural Research, 12, 265–275.

Acknowledgements: This post is based on a paper published with the support and guidance from my supervisors/ co-authors Dr Erandi Lokupitiya (University of Colombo, Sri Lanka), Dr Pramuditha Waidyarathne (Coconut Research Institute, Sri Lanka) and Dr Ravi Lokupitiya (University of Sri Jayewardenepura, Sri Lanka). 

———————————-
This blog is written by Cabot Institute member Charuni Pathmeswaran.
Charuni Pathmeswaran

How ancient warm periods can help predict future climate change

Posted on by janet.crompton

Several more decades of increased carbon dioxide emissions could lead to melting ice sheets, mass extinctions and extreme weather becoming the norm. We can’t yet be certain of the exact impacts, but we can look to the past to predict the future.

We could start with the last time Earth experienced CO2 levels comparable to those expected in the near future, a period 56m to 34m years ago known as the Eocene.

The Eocene began as a period of extreme warmth around 10m years after the final dinosaurs died. Alligators lived in the Canadian Arctic while palm trees grew along the East Antarctic coastline. Over time, the planet gradually cooled, until the Eocene was brought to a close with the formation of a large ice sheet on Antarctica.

During the Eocene, carbon dioxide (CO2) concentrations in the atmosphere were much higher than today, with estimates usually ranging between 700 and 1,400 parts per million (ppm). As these values are similar to those anticipated by the end of this century (420 to 935ppm), scientists are increasingly using the Eocene to help predict future climate change.

We’re particularly interested in the link between carbon dioxide levels and global temperature, often referred to as “equilibrium climate sensitivity” – the temperature change that results from a doubling of atmospheric CO2, once fast climate feedbacks (such as water vapour, clouds and sea ice) have had time to act.

To investigate climate sensitivity during the Eocene we generated new estimates of CO2 throughout the period. Our study, written with colleagues from the Universities of Bristol, Cardiff and Southampton, is published in Nature.

Reconstruction of the 40m year old planktonic foraminifer Acarinina mcgowrani.
Richard Bizley (www.bizleyart.com) and Paul Pearson, Cardiff University, CC BY

As we can’t directly measure the Eocene’s carbon dioxide levels, we have to use “proxies” preserved within sedimentary rocks. Our study utilises planktonic foraminifera, tiny marine organisms which record the chemical composition of seawater in their shells. From these fossils we can figure out the acidity level of the ocean they lived in, which is in turn affected by the concentration of atmospheric CO2.

We found that CO2 levels approximately halved during the Eocene, from around 1,400ppm to roughly 770ppm, which explains most of the sea surface cooling that occurred during the period. This supports previously unsubstantiated theories that carbon dioxide was responsible for the extreme warmth of the early Eocene and that its decline was responsible for the subsequent cooling.

We then estimated global mean temperatures during the Eocene (again from proxies such as fossilised leaves or marine microfossils) and accounted for changes in vegetation, the position of the continents, and the lack of ice sheets. This yields a climate sensitivity value of 2.1°C to 4.6°C per doubling of CO2. This is similar to that predicted for our own warm future (1.5 to 4.5°C per doubling of CO2).
Our work reinforces previous findings which looked at sensitivity in more recent time intervals. It also gives us confidence that our Eocene-like future is well mapped out by current climate models.

Fossil foraminifera from Tanzania – their intricate shells capture details of the ocean 33-50m years ago.
Paul Pearson, Cardiff University, CC BY

Rich Pancost, a paleoclimate expert and co-author on both studies, explains: “Most importantly, the collective research into Earth history reveals that the climate can and has changed. And consequently, there is little doubt from our history that transforming fossil carbon underground into carbon dioxide in the air – as we are doing today – will significantly affect the climate we experience for the foreseeable future.”

Our work also has implications for other elements of the climate system. Specifically, what is the impact of higher CO2 and a warmer climate upon the water cycle? A recent study investigating environmental change during the early Eocene – the warmest interval of the past 65m years – found an increase in global precipitation and evaporation rates and an increase in heat transport from the equator to the poles. The latter is consistent with leaf fossil evidence from the Arctic which suggests that high precipitation rates were common.

However, changes in the water cycle are likely to vary between regions. For example, low to mid latitudes likely became drier overall, but with more intense, seasonal rainfall events. Although very few studies have investigated the water cycle of the Eocene, understanding how this operates during past warm climates could provide insights into the mechanisms which will govern future changes.
The Conversation
———————–
This blog was written by Cabot Institute member Gordon Inglis, Postdoctoral Research Associate in Organic Geochemistry, University of Bristol and Eleni Anagnostou, Postdoctoral Research Fellow, Ocean and Earth Science, University of Southampton

This article was originally published on The Conversation. Read the original article.

How accurate are the media on climate change and extreme weather events?

Posted on by janet.crompton

I’ve always appreciated the environment, but had previously taken on the role of spectator. I credit this magnificent city of ours with inspiring me to change my passive respect of nature to taking an active role in trying to preserve it. The strong sense of community in Bristol and the green-mindedness of its residents is infectious, and is evident in the number of fantastic projects we have which are led by the people and by our local government.

I craved more information about our environment so started attending lectures and events that are regularly held by the Cabot Institute and various departments across the university. As my insight to the issues we face grew, I realised I needed to increase my understanding and hopefully align my career in a way in which I could have a positive impact. I decided to enrol in a masters in Climate Change Science and Policy so I could appreciate the scientific intricacies rather than relying on what I heard, and what I read in the media.

My course enabled me to learn about climate modelling and the difficulties of implementing environmental policies, not just logistically but in terms of ethics and opinion. It is one thing to be passionate about science and research, it is quite another to communicate that to a non-specialist in a way that the magnitude and seriousness of climate change is realised. A warming climate will affect the entire globe and all sectors within it. Bridging the gap in knowledge between climate scientists and policy makers/society is therefore paramount. People often rely on the media as their main source of information and indeed it can successfully act as an education broker between scientists and the public. The seemingly omnipotent power of the media to mould opinion can be beneficial, but do we really know if what we’re reading is the truth?

I was offered the opportunity to explore this question, and it was the Environment Agency (EA) that requested the answers. Specifically, I conducted my dissertation on the accuracy of the UK media in reporting of extreme weather events. It may seem a rather unusual project to be proposed by the EA, so I shall explain. Within the organisation is a climate change branch, a part of which is the ‘Climate Ready Support Service’. Their objective is to provide advice and support to businesses in order to prevent and mitigate the effects of extreme weather events and climate change. The Environment Agency uses recent extreme weather events to exemplify realistic scenarios that could befall a vulnerable business.

The speed, scope and accessibility of the media makes it a valuable tool, during and immediately after a weather event. The fast-paced nature of modern reporting and social media necessitates that to some extent the EA relies on information from news organisations. Additionally, there are vastly more journalists than there are staff in the ‘Climate Ready Support Service’ therefore media reliance is essential. When the EA republishes this information it must be relevant, accurate and consistent, and it was my mission to quantify the reliability of UK media and to assess the confidence that the EA can have in it.

I was not able to analyse all UK media so I studied a selected sample from the Guardian, the Telegraph and the Mirror. I chose them because they contain a mix of broadsheet/tabloid, political affiliations and demographics. I analysed sixty two articles across three extreme weather events: ex-Hurricane Bertha (2014), the spring floods (2012) and the Birmingham tornado (2005). This provided a range of recent short, high impact events and longer-lasting cumulative ones. I conducted content analysis on each article, breaking the text up into study units that could be verified by official sources such as government documentation, academic journals and weather data. Media accuracy is not as straightforward as being right or wrong, not just the objective facts. Subjective inaccuracies also play a part, and can fundamentally alter the final message or mislead the reader from the truth. I categorised these as omission of information, exaggeration/under-exaggeration, personalisation, sensationalism and general confusion.

The results suggest that overall the UK media is 77.9% accurate. The Guardian achieved the highest overall accuracy (83.8%), followed by the Telegraph (76.2%) and the Mirror obtained the lowest accuracy rate (72.5%). Of more consequence to the EA is objective (factual) accuracy as opposed to subjective accuracy, and, the Guardian is the most reliable of the three publications in this respect (94.3%). Even though it is a broadsheet, the Telegraph was less objectively accurate than the Mirror with 85.8% and 87.3% accuracy respectively. Across all three publications, factual inaccuracies such as measurements, geolocations, timings, names etc. were most prevalent with 30%. This was followed by omission/addition as the next most common error (27%). Exaggeration was also significantly evident in the press accounting for 17% of the total inaccuracies.

What does this mean for the EA? This research hopefully clarifies which publications are worth relying on most heavily when obtaining their information. I would still recommend the agency continue to conduct their own internal fact checks because evidently there are still errors. Additionally, it was a one person study, with only one perspective and a limited sample size. As with any research, there’s always more that can be done to validate the findings and as this was the first study to investigate media accuracy of extreme weather events, more is warranted before sweeping conclusions can be made.

What I found interesting was that of the sixty two articles analysed only four of them mentioned climate change within the content. It is the EAs aim to embed climate change messages within all aspects of their organisation, and with the projected increase of such events I would have expected more linkage in the media. After interviewing some journalists a lot of them agreed that climate change should be associated with not just extreme weather stories, but all topics such as education, health and finance. There are practical limitations in achieving this but perhaps in the future, climate change will always be considered in all aspects of our global society. For now we should remain hopeful that we make some significant steps forward after the United Nations Climate Summit in December, and that Bristol continues its European Green Capital ethos into 2016 and beyond.

It was a great experience knowing that my work might have a real world impact and my contacts in the Environment Agency were really helpful throughout the process. I am now working within the Sustainability Department here at the University of Bristol with the aim of reducing our environmental impact by implementing the S-Labs Initiative (Safe, Secure, Sustainable Labs).

—————————–
This blog is written by Anna Lewis who recently graduated from the Climate Change Science and Policy MSc at the University of Bristol.  As part of her course she undertook a Cabot Institute pilot project called Community Based Learning which connects postgraduate students with organisations in order to help them solve a real-world problem.  If your organisation would like to get involved in Community Based Learning with the University, please contact cabot-cbl@bristol.ac.uk.

Anna Lewis

Anna now works at the University implementing sustainable laboratories throughout the institution.

New challenges to the UK fruit supply chain

Posted on by janet.crompton
By Colin Smith, CC BY-SA 2.0

I was lucky to write my dissertation for the MSc degree in Environmental Policy and Management on a topic that is crucial, needs thorough examination, and is of uttermost interest to me. The project explored the impact of extreme weather events on resilience of the fruit supply chain in the UK with a case study of the UK apple supply chain. This project was done under the dissertation partnership scheme and was proposed by the Department for Environment, Food and Rural Affairs (DEFRA).

This project drew on several other studies conducted in this field, indicating the need to assess the vulnerability of the UK food supply to climate change, and extreme weather in particular. The most recent project was performed by the Cranfield University on behalf of DEFRA and estimated the resilience of the UK wheat and potato supply chains towards extreme weather. Therefore, it was agreed that I would focus on another supply chain to contribute to the knowledge necessary for the development of adaptation strategies and delivering advice to industry.

The apple supply chain was chosen for the case study as apples are characterized by the largest UK home production among fruits grown in the UK. The main research objectives were:

  1. Explore key vulnerabilities of fruit production to extreme weather by conducting literature review.
  2. Investigate impacts of extreme weather on apple home production.
  3. Evaluate factors affecting resilience of imports and retail of apples.
  4. On the basis of the case study on apples, determine factors affecting supply chain resilience for other types of fruits.
  5. Formulate recommendations on enhancing general fruit supply resilience.

The literature review revealed several key vulnerabilities of fruit development: winter chilling (for apples, 1000-1500 cumulative chilling hours at a temperature lower than 7°C are required over winter for successful development of the fruit), spring frost, rainfall, pests and diseases. Resilience of the apple supply chain was studied using a case study as the research strategy. Interviews and questionnaires were selected as methods for data collection. Interviews were targeted at all-UK fruit growers’ organizations, major importing companies, several large farms, and UK supermarkets, which yielded altogether 17 interviews. In addition, self-administered questionnaires were targeted specifically at apple growers in the UK irrespective of the region. 20th Century Reanalysis (V2) data was used to assess the trend in winter chilling hours in the UK.

I was very curious about the project as I was feeling that my research could indeed contribute to the understanding of the influence of extreme weather on food security in the UK. It was an amazing experience to talk to farmers, fruit producers and their organisations to actually hear real stories on how climate change affects them and what can be done and what they do to adapt.

Responses from the questionnaires and interviews revealed that farmers have experienced impact of extreme weather, but it has not been detrimental to the apple growing industry so far. The conducted analysis of the winter chilling trend has revealed its current decline and indicated the same decreasing tendency for the future. Additionally, it showed that the period of the hours with the air temperature less than 7°C is becoming warmer. The breeding of low chill plant varieties (cultivars) is probably the most obvious solution to insufficient chilling, the other ones being defoliation and temperature treatments and chemical breaking. However, it is difficult to breed new cultivars, and this takes a long time.

The well-designed contingency plan, good relationship with suppliers and their diversification, as well as sound knowledge of apple growing seasons in different countries are considered to be the key factors making the apple supply chain resilient from the point of view of importers and supermarket representatives. A long shelf life and cheap transportation conditions add to the resilience. Although respondents acknowledged that they do encounter problems related to extreme weather events, they have always managed to tackle them and do not perceive them as threatening UK supply.

Pear orchard. By Jonathan Billinger, CC BY-SA 2.0

The same conclusions about the impact of extreme weather events refer to pears as they have the most similar vulnerabilities to apples in terms of extreme weather. Cherries are now increasingly grown under plastic covers, which implies that impact of hail and wind is less of a problem for them. Poly tunnel or glass protection is used for soft fruit except for blackcurrants that are grown in the field. However, protection is removed for winter, therefore, extreme rainfall and flooding and winter chilling still might be a problem. Winter chilling is projected to be more of an issue for apples, cherries, European plums, blackcurrants and raspberries, as these require a considerable amount of chilling hours (from 800 to 1500-1700).

Importers build their contingency plans for all types of fruits, and none of the respondents mentioned any problems with their supply. Given the favourable financial situation of the UK, these considerations may entail that no matter the potential impacts of the extreme weather in the UK in the future, the fruit supply chain will always be resilient for the end consumer. However, this situation is not encouraging for farmers as the predicted increase in extreme weather events will potentially mean losses in their production or even complete closure of their business. The option of moving production to the north to obtain more winter chilling does not feel feasible as orchards are very expensive and it takes several years to obtain the first yield. Moreover, there are apparent complications in terms of moving home and the whole business to another region. In order to prevent this, an increased knowledge transfer is needed between horticulture and climate scientists and individual farmers to help them prepare for extreme weather as well as enable to take the necessary measures. Financial support for purchasing advanced scab detecting and moisture sensing equipment, and taking hail insurance, might be needed.

Hail nets over apple trees, like these in France, may become more common in the UK as more extreme weather takes place. Image credit: Wikimedia Commons, Aups.

The study concludes that in general the fruit supply chain in the UK is quite resilient for the end consumer, importing industry and retail, with growers potentially having more problems in terms of the impact of extreme weather on the crop in the future. In the first place, this might be caused by a decrease in winter chilling.

Despite the fact that in general the respondents were indicating the same set of problems, which was assuring for me, there was a clear tendency for academic staff in different universities I contacted and representatives of farmers’ unions to focus more on winter chilling in comparison to individual farmers. This might be explained by the difficulty in assessing changes in winter chilling without actually conducting analysis in this field. It is very interesting to know how climate change may impact food security by altering winter chilling patterns, which is not obvious, not easy to notice or track. At the same time, if measures for development of new low-chill cultivars are not taken now, a decline in apple production may appear unexpectedly.

Certainly, the study has its limitations. These included time constraints due to the fixed time frame for conducting an MSc dissertation (there is so much more to explore on the subject!), lack of accurate extreme weather predictions linked to uncertainty in climate models and inability to make accurate attributions of an extreme event to a change in apple production unless it is an obvious event which caused immediate damage (like hail, for example). However, despite these limitations, I hope that my research will help the UK Government deliver necessary advice to industry. I have always felt that the topic of my dissertation is important, and for me it was very rewarding to know that my work is really needed.

————————————-
This blog was written by Evgeniia Kostianaia, who studied an MSc in Environmental Policy and Management in 2014-2015 at the University of Bristol.

Evgeniia Kostianaia

Find out more about the Cabot Institute supported Community Based Learning Projects at the University of Bristol or contact cabot-cbl@bristol.ac.uk if you would like a student to conduct a research project for your organisation.

Professor Dame Julia Slingo: Modelling climate risk

Posted on by janet.crompton

When Professor Dame Julia Slingo visited the Cabot Institute last week, her message was clear: We need to look at climate risk in real world contexts.

Dame Julia was in the city to receive a Cabot Institute Distinguished Fellowship, which involved giving a talk about her work as a world leading meteorologist and Chief Scientist at the Met Office.

One of the first things she highlighted was that climate change isn’t isolated from other pressures like population growth and limited resources, so we need to understand the risks it poses in a real world context. We need to define the effects it may have on the security of food, water, health and energy around the world, and use the science as a guide to define an evidence-based and cost effective plan of action going forward. This, she said, is “one of the greatest challenges of the 21st century”.

Are we making extreme weather worse?

Today, the huge global population boom is putting an ever increasing strain on limited resources like land and water, which are also at risk from the cyclical climate variations that occur naturally. The big and controversial question is whether climate change caused by human activity has exacerbated the problem.

Dame Julia described an annual report produced by the American Meteorological Society (AMS) that analyses extreme weather events around the world each year, aiming to determine whether the effects were magnified by anthropogenic climate change. As she pointed out, it is important that we recognise that not every bit of bad weather can be attributed to climate change, however the AMS often do find that we have played a role in making the situation worse.

One example she picked out was 2012’s Hurricane Sandy, which killed 233 people across eight countries in central and north America. The AMS report found that if sea level had been at the level that it was 50 years ago, the devastating effects of the storm would not have been as bad. It also suggested that continuing on our current path of climate change will mean minor storms will have increasingly severe impacts, leading to Sandy-level hurricanes more frequently in the future.

“We need a more nuanced discussion”

Last year was the warmest on UK record, making a total of 8 out of 10 of our hottest years having occurred since 2002. While of course there is variability in our climate from year to year and even decade to decade, intricate scientific climate models have shown that these record-breaking UK temperatures are made ten times more likely due to anthropogenic climate change.

While we may prefer a hot summer, temperatures don’t change uniformly across the entire planet. Worryingly, the Arctic is warming twice as fast as the rest of the planet, leading to a huge decrease in the amount of sea ice cover and corresponding sea level rise, which is already threatening communities living on low lying islands. Dame Julia reminded us all that it’s not as simple as trying to prevent a 2°C global temperature increase. The danger that climate change poses depends on who you are and where you live, and we need models to show what the risks will be.

Predicting climate risk

So how can we predict what the effects of climate change will be across the world? It begins with having a sophisticated model of the current global system. The Met Office has led decades of climate modelling, producing incredibly sophisticated simulations of climate systems on both short term (weather) and long term (climate change) scales.

I was absolutely amazed by the intricacy of these models. Millions of lines of computer code recreate the true physical nature of the planet, to the extent where large scale meteorological patterns like El Niño are emergent properties of the model, that is to say that they are a result of the basic physics encoded in the model, rather than being specifically programmed into it.

By altering the model with new data taken from the present extent of climate change or its predicted level in the future, the Met Office can model the global response at incredible resolution, showing the specific risks posed with increasingly detailed clarity (while still incorporating the inherent uncertainties present in all models). These models can then be used to test potential mitigation approaches and of course inform the global communities of the dangers they face.

What can we do?

Dame Julia explained that her role as Chief Scientist is to determine the needs of the people around the world, their risk tolerance and the information they require to make their own decisions. Science, she says, has a lot to offer in enabling governments to make wise, informed and efficient decisions with how best to spend their funds within the wider context of other societal issues, upholding the global securities of food, water, health and energy for the future.

Flooded Pakistan



Image: “There is no evidence to counter the basic premise that a warmer world will lead to more intense daily and hourly rain events” – Professor Dame Julia Slingo


—————————————-
This blog is written by Cabot Institute member Sarah Jose, Biological Sciences, University of Bristol.

 
Sarah Jose

Why we must Bridge the Gap

Posted on by janet.crompton

Much of the climate change of the past century has been caused by our burning of fossil fuels. And without a change in that fossil fuel use, continued climate change in the next century could have devastating impacts on our society. It is likely to bring increased risk and hazards associated with extreme weather events. Refugee crises could be caused by rising sea levels or droughts that make some nations uninhabitable. Climate change will also make our world a more uncertain place to live, whether that be uncertainty in future rainfall patterns, the magnitude of sea level rise or the response of global fisheries to ocean acidification.  This uncertainty is particularly problematic because it makes it so much harder for industry or nations to plan and thrive.  Or to grapple with the other great challenge facing humanity – securing food, water and energy for 7 billion people (and growing).  Because of this, most nations have agreed that global warming should be held below 2°C.

Flooding on Whiteladies Road, Bristol. Image credit Jim Freer

These climatic and environmental impacts will be felt in the South West of England.  We live in an interconnected world, such that drought in North America will raise the price of our food. The effects of ocean acidification on marine ecosystems and UK fisheries remain worryingly uncertain. The floods of last winter could have been a warning of life in a hotter and wetter world; moreover, it will only become harder to protect our lowlands from not only flooding but also salt water incursions as sea level rises.  The proposed Hinkley Point nuclear power station will have an installation, operating and decommissioning lifetime of over 100 years; what added risks will it face from the combination of more severe weather, storm surges and rising sea level?  Climate change affects us all – globally, nationally and locally in the 2015 European Green Capital.

That requires reductions in emissions over the next decade.  And it then requires cessation of all fossil fuel emissions in the subsequent decades.  The former has been the subject of most negotiations, including the recent discussions in Lima and likely those in Paris at the end of this year. The latter has yet to be addressed by any international treaty. And that is of deep concern because it is the cessation of all fossil fuel emissions that is most difficult but most necessary to achieve.  Carbon dioxide has a lifetime in the atmosphere of 1000s of years, such that slower emissions will only delay climate change.  That can be useful – if we must adapt to a changing world, having more time to do so will be beneficial. However, it is absolutely clear that emissions must stop if we are to meet our target of 2°C.  In fact, according to most climate models as well as the geological history of climate, emissions must stop if we are to keep total warming below 5°C.

In short, we cannot use the majority of our coal, gas and petroleum assets for energy.  They must stay buried.

Can we ‘geoengineer’ our way to alternative solution?  Not according to recent research. Last November, a Royal Society Meeting showcased the results of three UK Research Council Funded investigations of geoengineering feasibility and consequences. They collectively illustrated that geoengineering a response to climate change was at best complicated and at worst a recipe for disaster and widespread global conflict.  The most prominent geoengineering solution is to offset the greenhouse gas induced rise in global temperatures via the injection of stratospheric particles that reflect some of the solar energy arriving at Earth.  However, on the most basic level, a world with elevated CO2 levels and reflective particles in the atmosphere  is not the same as a world with 280 ppm of CO2 and a pristine atmosphere. To achieve the same average global temperature, some regions will be cooler and others warmer.  Rainfall patterns will differ: regional patterns of flood and drought will differ. Even if it could be done, who are the arbitrators of a geoengineered world?  The potential for conflict is profound.

In short, the deus ex machina of geoengineering our climate is neither a feasible nor a just option.  And again, the conclusion is that we cannot use most of our fossil fuels.

One might argue that we can adapt to climate change: why risk our economy now when we can adapt to the consequences of climate change later? Many assessments suggest that this is not the best economic approach, but I understand the gamble: be cautious with a fragile economy now and deal with consequences later.  This argument, however, ignores the vast inequity associated with climate change.  It is the future generations that will bear the cost of our inaction.  Moreover, it appears that the most vulnerable to climate change are the poorest – and those who consume the least fossil fuels.  Those of us who burn are not those who will pay.  Arguably then, we in the UK have a particular obligation to the poor of the world and of our own country, as well as to our children and grandchildren, to soon cease the use of our fossil fuels.

Energy is at the foundation of modern society and it has been the basis for magnificent human achievement over the past 150 years, but it is clear that obtaining energy by burning fossil fuels is warming our planet and acidifying our oceans.  The consequences for our climate, from extreme weather events to rising sea levels, is profound; even more worrying are the catastrophic risks that climate change poses for the food and water resources on which society depends.  It is now time for us to mature beyond the 19th and 20th century fossil-fuel derived energy to a renewable energy system of the 21st century that is sustainable for us and our planet.

We must bridge the gap.

—————————————–
Sign up to our weekly newsletter for all the latest news, events and opportunities at https://bristol.ac.uk/cabot/news/subscribe. Find out more about our unique Master's by Research in Global Environmental Challenges at https://bristol.ac.uk/cabot-masters.